Open AccessSpatial- and energy-resolved photoemission electron from plasmonic nanoparticles in multiphoton regime
Author(s) -
Peng Lang,
Xiaowei Song,
Boyu Ji,
Haiyan Tao,
Yusheng Dou,
Xun Gao,
Zuoqiang Hao,
Jingquan Lin
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.006878
Subject(s) - plasmon , x ray photoelectron spectroscopy , photoemission electron microscopy , femtosecond , materials science , inverse photoemission spectroscopy , electron , atomic physics , surface plasmon , angle resolved photoemission spectroscopy , laser , photoemission spectroscopy , molecular physics , optics , optoelectronics , condensed matter physics , physics , electronic structure , electron microscope , nuclear magnetic resonance , quantum mechanics
Spatial-resolved photoelectron spectra have been observed from plasmonic metallic nanostructure and flat metal surface by a combination of time-of-flight photoemission electron microscope and femtosecond laser oscillator. The photoemission's main contribution is at localized 'hot spots,' where the plasmonic effect dominates and multiphoton photoemission is confirmed as the responsible mechanism for emission in both samples. Photoelectron spectra from hot spots exponentially decay in high energy regimes, smearing out the Fermi edge in Au flat surface. This phenomenon is explained by the emergence of above threshold photoemission that is induced by plasmonic effect; other competing mechanisms are ruled out. It is the first time that we have observed the emergence of high kinetic energy photoelectron in weak field region around 'hot spot.' We attribute the emergence of high kinetic energy photoelectron to the drifting of the liberated electron from plasmonic hot spot and driven by the gradient of plasmonic field.